Mid-Jurassic age for the Botany Bay Group: implications for Weddell Sea Basin creation and southern hemisphere biostratigraphy
New U–Pb zircon ion-microprobe ages from the alluvial conglomerates and flood plain sediments of the Botany Bay Group demonstrate that sedimentation occurred at c. 167 Ma, coeval with rift-related silicic volcanism in the northern Antarctic Peninsula. In contrast, rift-related volcanism and sediment...
Published in: | Journal of the Geological Society |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Geological Society of London
2005
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/1818/ |
Summary: | New U–Pb zircon ion-microprobe ages from the alluvial conglomerates and flood plain sediments of the Botany Bay Group demonstrate that sedimentation occurred at c. 167 Ma, coeval with rift-related silicic volcanism in the northern Antarctic Peninsula. In contrast, rift-related volcanism and sedimentation in the southern Antarctic Peninsula (Latady Basin) occurred at c. 183 Ma. The new data indicate that syn-rift sedimentation and volcanism was diachronous from south to north, consistent with early opening of the Weddell Sea embayment by anti-clockwise rotation of the Antarctic Peninsula in the Mid-Jurassic. A definitive date for the Botany Bay Group floras has important implications for Southern Hemisphere biostratigraphic correlations. |
---|